Glassfish example source code file (GadgetHandlers.java)

This example Glassfish source code file (GadgetHandlers.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Glassfish tags/keywords

gadgethandlers, gadgetmodule, gadgetmodule, handler, handlerinput, handlerinput, handleroutput, illegalargumentexception, io, net, network, object, object, string, string, stringtokenizer, url, util

The Glassfish GadgetHandlers.java source code

/*
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 *
 * Copyright (c) 1997-2010 Oracle and/or its affiliates. All rights reserved.
 *
 * The contents of this file are subject to the terms of either the GNU
 * General Public License Version 2 only ("GPL") or the Common Development
 * and Distribution License("CDDL") (collectively, the "License").  You
 * may not use this file except in compliance with the License.  You can
 * obtain a copy of the License at
 * https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
 * or packager/legal/LICENSE.txt.  See the License for the specific
 * language governing permissions and limitations under the License.
 *
 * When distributing the software, include this License Header Notice in each
 * file and include the License file at packager/legal/LICENSE.txt.
 *
 * GPL Classpath Exception:
 * Oracle designates this particular file as subject to the "Classpath"
 * exception as provided by Oracle in the GPL Version 2 section of the License
 * file that accompanied this code.
 *
 * Modifications:
 * If applicable, add the following below the License Header, with the fields
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 * and therefore, elected the GPL Version 2 license, then the option applies
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package org.glassfish.admingui.common.gadget;

import com.sun.jsftemplating.annotation.Handler;
import com.sun.jsftemplating.annotation.HandlerInput;
import com.sun.jsftemplating.annotation.HandlerOutput;
import com.sun.jsftemplating.layout.LayoutDefinitionManager;
import com.sun.jsftemplating.layout.descriptors.handler.HandlerContext;
import com.sun.jsftemplating.layout.descriptors.handler.HandlerDefinition;
import com.sun.jsftemplating.layout.descriptors.handler.OutputTypeManager;
import com.sun.jsftemplating.util.FileUtil;

import java.io.UnsupportedEncodingException;
import java.net.URL;
import java.net.URLDecoder;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.StringTokenizer;

import org.glassfish.admingui.common.util.GuiUtil;
import org.glassfish.admingui.common.util.JSONUtil;

import org.jvnet.hk2.config.ConfigParser;
import org.jvnet.hk2.config.DomDocument;


/**
 *  <p>	This class provides access to {@link GadgetModule}s.  It also has a
 *	nice JSON utility for converting JavaBean Objects (and primitives,
 *	Collections, Maps, Strings, etc.) to JSON.</p>
 *
 *  @author Ken Paulsen	(ken.paulsen@sun.com)
 */
public class GadgetHandlers {

    /**
     *	<p> Default constructor.

     */
    public GadgetHandlers() {
    }

    /**
     *	<p> This handler returns a {@link GadgetModule} for the named
     *	    gadget.  The <code>name should either be a complete URL,
     *	    or a context-root relative path to the gadget XML file (this
     *	    also includes .xml files stored in .jar's / plugins).</p>
     */
    @Handler(id="gf.getGadgetModule",
	input = {
	    @HandlerInput(name="name", type=String.class, required=true)
	},
	output = {
	    @HandlerOutput(name="module", type=GadgetModule.class)
	})
    public static void getGadgetModule(HandlerContext handlerCtx) {
	String gadgetName = (String) handlerCtx.getInputValue("name");
	URL url = null;
	try {
	    if (!gadgetName.contains("://")) {
		// Treat as a path...
		url = FileUtil.searchForFile(gadgetName, null);
	    }
	    if (url == null) {
		url = new URL(gadgetName);
	    }
	} catch (Exception ex) {
	    throw new IllegalArgumentException("Cannot creaqte URL from '"
		+ gadgetName + "'!", ex);
	}
	GadgetModule module = getGadgetModule(url);
	handlerCtx.setOutputValue("module", module);
    }

    /**
     *	<p> This method returns a {@link GadgetModule} for the given URL.

     */
    public static GadgetModule getGadgetModule(URL url) {
	if (url == null) {
	    return null;
	}
// FIXME: Cache?
	// Get our parser...
	ConfigParser parser = new ConfigParser(GuiUtil.getHabitat());
	String id = null;

	// Read the document...
	DomDocument doc = parser.parse(url);

	// Get the GadgetModule
	GadgetModule module = (GadgetModule) doc.getRoot().get();

	return module;
    }

    /**
     *	<p> This handler will invoke another handler.  This allows a generic
     *	    handler to invoke another one and return the response(s), if
     *	    any.</p>
     *
     *	<p> The following are the inputs are supported:

     *	    <ul>
handler - (required) This input specifies the
     *		    handler which should be invoked.</li>
     *		<li>args - (required) This specifies all of the
     *		    arguments to be passed to the handler (both input and
     *		    output arguments).  The value of this should be a String
     *		    formatted as a comma separated list of name-value pairs
     *		    (which are themselves separated by colons (:).  The value
     *		    of the name-value pairs should be URL encoded (so that
     *		    commas are escaped).</li>
     *		<li>depth - (optional) This property specifies the max
     *		    depth of nesting for any output values from the handler.
     *		    Output values are encoded in JSON.  This prevents infinite
     *		    looping in the case where an Object refers to itself (or in
     *		    the case wehre there is unnecessarily deep data
     *		    structures).</li>
     */
    @Handler(id="gf.invokeHandler",
	input = {
	    @HandlerInput(name="handler", type=String.class, required=true),
	    @HandlerInput(name="args", type=String.class, required=true),
	    @HandlerInput(name="depth", type=Integer.class, required=false)
	},
	output = {
	    @HandlerOutput(name="values", type=String.class)
	})
    public static Object invokeHandler(HandlerContext handlerCtx) {
	// First find the HandlerDefinition
	String handlerName = (String) handlerCtx.getInputValue("handler");
	HandlerDefinition handlerDef = LayoutDefinitionManager.getGlobalHandlerDefinition(handlerName);
	if (handlerDef == null) {
	    throw new IllegalArgumentException("Handler '" + handlerName
		    + "' not found!");
	}

	// Before working with the new Handler, save the old Handler...
	com.sun.jsftemplating.layout.descriptors.handler.Handler oldHandler =
		handlerCtx.getHandler();

	// Create the Handler to invoke...
	com.sun.jsftemplating.layout.descriptors.handler.Handler handler =
	    new com.sun.jsftemplating.layout.descriptors.handler.Handler(handlerDef);

	// Now try to get the inputs / outputs
	List<String> outputNames = new ArrayList();
	String args = (String) handlerCtx.getInputValue("args");
	StringTokenizer tok = new StringTokenizer(args, ",");
	String nvp, name, value;
	int colon;
	while (tok.hasMoreTokens()) {
	    // Get the NVP...
	    nvp = tok.nextToken();
	    colon = nvp.indexOf(':');
	    if (colon == -1) {
		throw new IllegalArgumentException(
		    "Handler I/O name:value must be separated by a ':'!");
	    }
	    name = nvp.substring(0, colon).trim();
	    value = nvp.substring(colon+1).trim();

	    // URL decode 'value'...
	    try {
		value = URLDecoder.decode(value, "UTF-8");
	    } catch (UnsupportedEncodingException ex) {
		throw new IllegalArgumentException(
		    "Unable to decode value, this is not normal!", ex);
	    }

	    // See if it is an input...
	    if (handlerDef.getInputDef(name) != null) {
		// It's an input...
		handler.setInputValue(name, value);
	    } else {
		// Assume it's an output mapping...
		handler.setOutputMapping(name, value, OutputTypeManager.EL_TYPE);
		outputNames.add(name);
	    }
	}

	// We have the new handler (yea!), invoke it...
	List<com.sun.jsftemplating.layout.descriptors.handler.Handler> handlers =
	    new ArrayList<com.sun.jsftemplating.layout.descriptors.handler.Handler>(1);
	handlers.add(handler);
	Object result = handlerCtx.getLayoutElement().
		dispatchHandlers(handlerCtx, handlers);

	// Now... lets get the output values from the "child" handler...
	Map<String, Object> outputValues = new HashMap();
	String outName;
	Iterator<String> it = outputNames.iterator();
	while (it.hasNext()) {
	    // For each output specified, save it in a Map to be encoded later
	    outName = it.next();
	    outputValues.put(outName, handler.getOutputValue(handlerCtx, outName));
	}

	// Now we're done with the "child" Handler, restore this Handler...
	handlerCtx.setHandler(oldHandler);

	// Finally, translate the Map to JSON and set the String as an output
	Integer depth = (Integer) handlerCtx.getInputValue("depth");
	if (depth == null) {
	    depth = 10;
	}
	handlerCtx.setOutputValue("values", JSONUtil.javaToJSON(outputValues, depth));

	return result;
    }
}